Narwhal (Monodon monoceros)

The narwhal (Monodon monoceros), often called the "unicorn of the sea," is a unique Arctic whale species best known for its long, spiral tusk—actually an elongated canine tooth that can grow up to 10 feet. Males use this tusk for sensing environmental changes and possibly mating displays. Living in frigid polar waters, narwhals dive deep to hunt fish and squid. Their elusive nature and mystical appearance have fueled legends for centuries. Despite their hardiness in extreme conditions, climate change threatens their icy habitat, making them one of the ocean's most fascinating yet vulnerable creatures.